Restructuring - Related Balance Sheet Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve - Beginning Balance	$ 40,125
Costs charged to expense	77,183	$ 6,418	$ 49,090
Cash (payments) receipts	(34,462)
Net assets disposed and impaired	901
Effect of change in exchange rates	(6,377)
Restructuring Reserve - Ending Balance	75,568	40,125
Employee severance costs
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve - Beginning Balance	37,654
Costs charged to expense	69,768
Cash (payments) receipts	(28,894)
Net assets disposed and impaired	0
Effect of change in exchange rates	(6,376)
Restructuring Reserve - Ending Balance	72,152	37,654
Asset Impairment and Net (Gain) Loss on Sale or Disposal [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve - Beginning Balance	0
Costs charged to expense	859
Cash (payments) receipts	42
Net assets disposed and impaired	901
Effect of change in exchange rates	0
Restructuring Reserve - Ending Balance	0	0
Other restructuring costs
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve - Beginning Balance	2,471
Costs charged to expense	6,556
Cash (payments) receipts	(5,610)
Net assets disposed and impaired	0
Effect of change in exchange rates	(1)
Restructuring Reserve - Ending Balance	$ 3,416	$ 2,471